Most garages will be able to source parts for your car same day or next day, depending on how rare your vehicle is. Klarius has over 95% of the demand for replacement exhausts in stock in its warehouse in the UK, so any Accredited Garage will have access to that stock via its main supplier/distributor.

Fitting an exhaust, CAT or DPF usually means the bolts holding the system to the car have to be removed, which will usually take a bit of time and skill, so not always a 5 minute job as you would imagine, but, in most cases, not something that should take more than a couple of hours.